It was announced on Twitter last week that the Opencaching.com listing site would be officially shut down on Friday 14th August, but that their devices would continue to support geocaching. The website now redirects to a Garmin page about geoaching

This is not to be confused with Opencaching.org.uk listing site.

I would advise that if you have any geocaches that were listed only on Opencaching.com that you remove them or list them on another listing site to avoid geolitter.